Patient-specific hip joint devices

ABSTRACT

A patient-specific acetabular resection guide includes a dome-shaped surface bounded by a periphery. The dome-shaped surface is a three-dimensional patient-specific surface designed to anatomically match and be received into an acetabulum of the patient, based on a three-dimensional image of a hip joint of the patient reconstructed from a medical scan of the hip joint. The resection guide includes a plurality of guiding formations defined on the resection guide and having patient-specific shapes and orientations for guiding corresponding osteotomies relative to the acetabulum for correcting hip dysplasia.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.12/973,214, filed Dec. 20, 2010, which a continuation-in-part of U.S.application Ser. No. 12/955,361, filed Nov. 29, 2010, which is acontinuation-in-part of U.S. application Ser. Nos. 12/938,905 and12/938,913, both filed Nov. 3, 2010, each of which is acontinuation-in-part of U.S. application Ser. No. 12/893,306, filed Sep.29, 2010, which is a continuation-in-part of U.S. application Ser. No.12/888,005, filed Sep. 22, 2010, which is a continuation-in-part of U.S.application Ser. No. 12/714,023, filed Feb. 26, 2010, which is: acontinuation-in-part of U.S. application Ser. No. 12/571,969, filed Oct.1, 2009, which is a continuation-in-part of U.S. application Ser. No.12/486,992, filed Jun. 18, 2009, and a continuation-in-part of U.S.application Ser. No. 12/389,901, filed Feb. 20, 2009, which is acontinuation-in-part of U.S. application Ser. No. 12/211,407, filed Sep.16, 2008, which is a continuation-in-part of U.S. application Ser. No.12/039,849, filed Feb. 29, 2008, which: (1) claims the benefit of U.S.Provisional Application No. 60/953,620, filed on Aug. 2, 2007, U.S.Provisional Application No. 60/947,813, filed on Jul. 3, 2007, U.S.Provisional Application No. 60/911,297, filed on Apr. 12, 2007, and U.S.Provisional Application No. 60/892,349, filed on Mar. 1, 2007; (2) is acontinuation-in-part U.S. application Ser. No. 11/756,057, filed on May31, 2007, which claims the benefit of U.S. Provisional Application No.60/812,694, filed on Jun. 9, 2006; (3) is a continuation-in-part of U.S.application Ser. No. 11/971,390, filed on Jan. 9, 2008, which is acontinuation-in-part of U.S. application Ser. No. 11/363,548, filed onFeb. 27, 2006; and (4) is a continuation-in-part of U.S. applicationSer. No. 12/025,414, filed on Feb. 4, 2008, which claims the benefit ofU.S. Provisional Application No. 60/953,637, filed on Aug. 2, 2007.

This application is continuation-in-part of U.S. application Ser. No.12/872,663, filed on Aug. 31, 2010, which claims the benefit of U.S.Provisional Application No. 61/310,752 filed on Mar. 5, 2010.

This application is a continuation-in-part of U.S. application Ser. No.12/483,807, filed on Jun. 12, 2009, which is a continuation-in-part ofU.S. application Ser. No. 12/371,096, filed on Feb. 13, 2009, which is acontinuation-in-part of U.S. application Ser. No. 12/103,824, filed onApr. 16, 2008, which claims the benefit of U.S. Provisional ApplicationNo. 60/912,178, filed on Apr. 17, 2007.

This application is also a continuation-in-part of U.S. application Ser.No. 12/103,834, filed on Apr. 16, 2008, which claims the benefit of U.S.Provisional Application No. 60/912,178, filed on Apr. 17, 2007.

The disclosures of the above applications are incorporated herein byreference.

INTRODUCTION

The present teachings provide various patient-specific guides andrelated implants for the hip joint.

SUMMARY

The present teachings provide a hip-joint device that includes apatient-specific acetabular resection guide. The acetabular resectionguide includes a dome-shaped surface bounded by a periphery. Thedome-shaped surface is a three-dimensional patient-specific surfacedesigned to anatomically match and be received into an acetabulum of thepatient, based on a three-dimensional image of a hip joint of thepatient reconstructed from a medical scan of the hip joint. Theresection guide includes a plurality of guiding formations defined onthe resection guide and having patient-specific shapes and orientationsfor guiding corresponding osteotomies relative to the acetabulum forcorrecting hip dysplasia.

In some embodiments, the acetabular resection guide include an annularflange extending from the periphery of the dome-shaped surface. Theannular flange has a patient-specific surface engageable to aperiacetabular area of the acetabulum of the patient. A plurality ofelongated slots are defined by the flange and oriented around theperiphery in a patient-specific orientation for guiding a cuttinginstrument to re-orient the acetabulum relative to the pelvis.

The present teachings also provide an implant for a femoral head of apatient. The implant includes a shell implantable on the femoral head ofthe patient and correcting a defect of the femoral head. The shell isdesigned preoperatively to have a patient-specific first surface forarticulation with the patient's acetabulum and a patient-specificperiphery mateable with a periphery of the defect. The shell caps thedefect and the first surface of the shell is continuous to a remaininghealthy surface of the femoral head. The defect can be a bone defect, acartilage defect or a combination thereof.

The present teachings provide a method for repairing a hip-joint. Themethod includes engaging an acetabulum of a pelvis of a patient with apatient-specific resection guide and positioning a patient-specificdome-shaped surface of the resection guide into a complementary surfaceof the acetabulum. The method also includes guiding a cutting instrumentthrough a first elongated slot of a flange surrounding the dome-shapedsurface, performing a first osteotomy through the first elongated slot,and correcting an orientation of the acetabulum.

In another embodiment, the method includes determining a firstpatient-specific osteotomy for re-orienting a patient's acetabulum tocorrect hip dysplasia. The method also includes designing apatient-specific resection guide having a patient-specific dome-shapedsurface complementary to the patient's acetabulum and a flangesurrounding the dome shaped surface, and designing a firstpatient-specific slot for guiding the first-patient-specific osteotomy.

Further areas of applicability of the present teachings will becomeapparent from the description provided hereinafter. It should beunderstood that the description and specific examples are intended forpurposes of illustration only and are not intended to limit the scope ofthe present teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present teachings will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an exemplary illustration of a patient in preparation of anacetabular implant procedure;

FIG. 1A is a perspective view of an acetabular guide according to thepresent teachings, the acetabular guide shown in relation to a patient'sanatomy;

FIG. 2 is an environmental perspective view of the acetabular guide ofFIG. 1A shown with an acetabular inserter holding an acetabular implantaccording to the present teachings;

FIG. 3 is a perspective view of the acetabular inserter and acetabularimplant of FIG. 2;

FIG. 3A is a perspective environmental view of an acetabular implantillustrating rotation about an anatomic axis A during insertionaccording to the present teachings;

FIG. 3B is a perspective environmental view of an acetabular implantillustrating rotation about an anatomic axis B during insertionaccording to the present teachings;

FIG. 4 is an exploded view of the acetabular inserter and acetabularimplant of FIG. 3;

FIG. 5 is an environmental view of a patient-specific acetabularresection guide according to the present teachings;

FIG. 6 is a perspective view of a patient-specific acetabular resectionguide according to the present teachings;

FIG. 6A is an anterior view of a hip joint illustrating an example ofhip dysplasia;

FIG. 6B is an anterior view of a hip joint illustrating an example of acorrected hip dysplasia according to the present teachings;

FIG. 6C is an anterior view of a hip joint illustrating an example ofplanned osteotomies according to the present teachings;

FIG. 7 is a perspective view of an exemplary acetabular implant;

FIG. 8 is perspective view of a pelvis showing a defective region;

FIG. 8A is a perspective view of a patient-specific augment for use inrelation to FIG. 8 according to the present teachings;

FIG. 8B is a perspective view of another patient-specific augment foruse in relation to FIG. 8 according to the present teachings;

FIG. 9 is a perspective view of an exemplary acetabular implant with apatient-specific augment according to the present teachings;

FIG. 10 is perspective view of a femoral head showing a bony defect;

FIG. 11 an environmental view of an exemplary patient-specific implantfor use in relation to FIG. 10 according to the present teachings;

FIG. 12 is perspective view of a femoral head showing a cartilagedefect; and

FIG. 13 an environmental view of an exemplary patient-specific implantfor use in relation to FIG. 12 according to the present teachings.

DESCRIPTION OF VARIOUS ASPECTS

The following description is merely exemplary in nature and is in no wayintended to limit the present teachings, applications, or uses.

The present teachings generally provide a patient-specific acetabularguide and associated inserter for use in orthopedic surgery, such as injoint replacement or revision surgery, for example. The patient-specificalignment guides can be used either with conventional orpatient-specific implant components prepared with computer-assistedimage methods. Computer modeling for obtaining three dimensional imagesof the patient's anatomy using MRI, CT or Other medical scans of thepatient's anatomy, the patient-specific prosthesis components, and thepatient-specific guides and templates can be designed using various CADprograms and/or software available, for example, by Materialise USA, AnnArbor, Mich.

Patient-specific alignment guides and implants are generally configuredto match the anatomy of a specific patient. The patient-specificalignment guides are generally formed using computer modeling based onthe patient's 3-D anatomic image and have an engagement surface that ismade to conformingly contact and match a three-dimensional image of thepatient's bone surface (with or without cartilage or other soft tissue),by the computer methods discussed above. The patient-specific alignmentguides can include custom-made guiding formations, such as, for example,guiding bores or cannulated guiding posts or cannulated guidingextensions or receptacles that can be used for supporting or guidingother instruments, such as drill guides, reamers, cutters, cuttingguides and cutting blocks or for inserting pins or other fastenersaccording to a surgeon-approved pre-operative plan. The patient-specificalignment guides can be used in minimally invasive surgery, and inparticular in surgery with multiple minimally-invasive incisions.Various alignment guides and preoperative planning procedures aredisclosed in commonly assigned and co-pending U.S. patent applicationSer. No. 11/756,057, filed on May 31, 2007; U.S. patent application Ser.No. 12/211,407, filed Sep. 16, 2008; U.S. patent application Ser. No.11/971,390, filed on Jan. 9, 2008, U.S. patent application Ser. No.11/363,548, filed on Feb. 27, 2006; and U.S. patent application Ser. No.12/025,414, filed Feb. 4, 2008. The disclosures of the aboveapplications are incorporated herein by reference.

As disclosed, for example, in above-referenced U.S. patent applicationSer. No. 11/756,057, filed on May 31, 2007; in the preoperative planningstage for a joint replacement or revision procedure, an MRI scan or aseries of CT scans of the relevant anatomy of the patient, such as, forexample, the entire leg of the joint to be reconstructed, can beperformed at a medical facility or doctor's office. The medical scandata obtained can be sent to a manufacturer. The medical scan data canbe used to construct a three-dimensional image of the joint and providean initial implant fitting and alignment in a computer file form orother computer representation. The initial implant fitting and alignmentcan be obtained using an alignment method, such as alignment protocolsused by individual surgeons.

The outcome of the initial fitting is an initial surgical plan that canbe printed or provided in electronic form with corresponding viewingsoftware. The initial surgical plan can be surgeon-specific, when usingsurgeon-specific alignment protocols. The initial surgical plan, in acomputer file form associated with interactive software, can be sent tothe surgeon, or other medical practitioner, for review. The surgeon canincrementally manipulate the position of images of implant components inan interactive image of the joint. Additionally, the surgeon can selector modify resection planes, types of implants and orientations ofimplant insertion. For example, the surgeon may select patient-specificanteversion and abduction angles for acetabular implants, as discussedbelow. After the surgeon modifies and/or approves the surgical plan, thesurgeon can send the final, approved plan to the manufacturer.

After the surgical plan is approved by the surgeon, patient-specificalignment guides can be developed using a CAD program or other imagingsoftware, such as the software provided by Materialise, for example,according to the surgical plan. The guides can be manufactured byvarious stereolithography methods, selective laser sintering, fuseddeposition modeling or other rapid prototyping methods. In someembodiments, computer instructions of tool paths for machining thepatient-specific alignment guides can be generated and stored in a toolpath data file. The tool path can be provided as input to a CNC mill orother automated machining system, and the alignment guides can bemachined from polymer, ceramic, metal or other suitable material, andsterilized. The sterilized alignment guides can be shipped to thesurgeon or medical facility, for use during the surgical procedure.

The present teachings provide a patient-specific acetabular guide andassociated inserter for inserting an acetabular implant in theacetabulum of a patient's pelvis in a guided orientation at least aboutfirst and second non-parallel anatomic axes. Referring to FIGS. 1, 3Aand 3B, the first anatomic axis indicated at “A”, passes through theacetabulum 82 of a patient's pelvis 80 (only half of the pelvis isshown) and is oriented generally in a superior/inferior directionrelative to the patient. The second anatomic axis is indicated at “B”and is substantially perpendicular to the first axis A. As describedbelow, the present teachings provide instruments and methods forguiding, orienting and positioning an acetabular implant 200 at aselected angle of anteversion relative to the axis A, as shown in FIG.3A, and at a selected angle of abduction relative to the axis B, as alsoshown in FIG. 3B. The anteversion and abduction angles can be determinedinteractive or other surgeon input and can be patient-specific.

Referring to FIG. 1A, an exemplary acetabular guide 100 according to thepresent teachings can include a first surface 108 for engaging an areasurrounding the acetabulum 82 and a second surface 110 opposite to thefirst surface 108. The acetabulum-engaging first surface 108 can becustom-made or patient-specific to conform and mirror an acetabular rimsurface 84 around the acetabulum 82 of a specific patient by usingthree-dimensional image of the acetabulum and surrounding pelvic area ofthe patient, as described above. The first surface 108 enables theacetabular guide to nest or closely mate relative to the acetabulum 82of the patient.

The acetabular guide 100 can be temporarily and removably attached tothe pelvis 80 using temporary fasteners 120, such as bone nails ortacks, for example, passing through corresponding holes 104 through theacetabular guide 100. The acetabular guide 100 can be annular with anopening defined by an inner surface 102. The inner surface 102 can be,for example, a cylindrical surface. The inner surface 102 can beoriented relative to the first and second surfaces 108, 110 of theacetabular guide 100 to provide a selected anteversion angle about thefirst axis A and a selected abduction angle relative to the axis B, asshown in FIGS. 2, 3A and 3B. The anteversion and abduction angles can besurgeon-selected and patient-specific and can be determined with surgeoninput during the preoperative planning for the specific patient.Anteversion angles can be, for example, in the range of about 10-20degrees forward relative to the first axis A, and adduction angles canbe in the range of about 40-50 degrees downward relative to the secondaxis B.

Referring to FIGS. 2-4, the acetabular guide 100 can be attached to thepelvis 80 around the acetabulum 72 after the acetabulum 82 has beenreamed and prepared for receiving the acetabular implant 200, such asthe Magnum™ acetabular cup commercially available from Biomet, Inc.,Warsaw, Ind. The acetabular implant 200 can be inserted into theprepared acetabulum 82 using an inserter 300 according to the presentteachings. The inserter 300, which can also function as an impactor, caninclude a handle 304 with a proximal impaction surface 318, a shaft 302and a guide-engaging portion 310 having a surface with a flat or planarportion 320. The guide-engaging portion 310 can have an outer surface312, which conforms to and is mateable with the inner surface 102 of theacetabular guide 100 for guiding the acetabular implant 200. The innersurface 102 and the outer surface 312 can be cylindrical.

Referring to FIG. 4, the inserter 300 can engage the acetabular implant200 via an intermediate member 250, such as the intermediate member ofthe Magnum™ system, which is commercially available from Biomet, Inc.,Warsaw, Ind. More specifically, the inserter 300 can include a distalportion 314, such as a ball-bearing bushing, which can be inserted andengage a receptacle 252 of the intermediate member 250. The acetabularimplant 200 can be mounted on the intermediate member 250 by aligning aplurality of fingers 254 of the intermediate member 250 withcorresponding cut-outs 202 on a peripheral edge of the acetabularimplant 200. The fingers 254 of the intermediate member 250 securelyengage the cut-outs 202 of the acetabular implant 200 when the distalportion/bushing 314 of the inserter 300 is pushed in and received in thereceptacle 252 of the intermediate member 250.

Referring to FIG. 2, the inserter 300 with the acetabular implant 200mounted thereon can be directed toward the acetabular guide 100. Theouter surface 312 of the guide engaging portion 310 of the inserter 300can be brought into contact with the inner surface 102 of the acetabularguide 100, guiding the acetabular implant 200 toward the selectedanteversion and abduction orientation through the acetabular guide 100.The outer surface 312 of the guide engaging portion 310 can also providean impaction-depth feedback by alignment with the inner surface 102 ofthe acetabular guide. Full impaction of the acetabular implant 200 intothe acetabulum 82 can be indicated when planar portion 320 and/or outersurface 312 of the guide-engaging portion 310 of the inserter 300 areflush with and do not protrude over and above the second surface 110 ofthe acetabular guide 100. Depth indicia 322 can also be provided on theinserter shaft 302 or on the guide-engaging portion 310 of the inserter300, as shown in FIG. 2.

After the acetabular implant 200 is fully seated in the acetabulum 82 inthe selected anteversion and abduction orientations, the inserter 300and intermediate member 250 can be removed. The temporary fasteners 120can be removed and the acetabular guide released.

The acetabular guide 100 can be made of any biocompatible material, suchas metal, ceramic or polymer. The acetabular guide 100 can beconstructed by various manufacturing methods depending of the selectedmaterial, including, for example, machining, casting, molding,stereolithography or other layer deposition methods. In one aspect, theacetabular guide 100 can be made of disposable plastic material.

For certain patients, acetabular implants may be implanted after certainhip joint abnormalities are corrected, such as for example, aftercorrecting developmental, congenital or other hip joint dysplasia orother misalignment between a femoral head 90 and the acetabulum 82 ofthe pelvis 80, as illustrated in FIG. 6A. In the exemplary illustrationof FIG. 6A, the center axis of the femoral head D is misaligned relativeto the center axis D′ of the acetabulum 82.

Hip dysplasia is a condition typically characterized by poor coverage ofthe superior and anterior surface of the femoral head, a shallowacetabulum and/or short femoral neck. Various surgical procedures havebeen developed to correct hip dysplasia, including periacetabularosteotomy methods, single open osteotomy, double osteotomy, and tripleosteotomy. Various osteotomy methods are known by the names of thesurgeons who developed the corrective surgical methods, such as, Salter,Bernese, and Gantz osteotomies, for example.

An exemplary surgical approach for correcting hip dysplasia includesperforming a series of controlled osteotomies, such as osteotomies 86,87, 88 around the acetabulum to separate the acetabulum from the pelvis,as illustrated in FIG. 6C. The surgeon can then re-orient or rotate theacetabulum 82 relative to the pelvis 80 and femoral head 90 to place theacetabulum 82 in a better position to cover and articulate with thefemoral head 90. In some cases, correction of hip joint dysplasia mayrequire a single osteotomy 86 at the iliac area, for example, such thatthe acetabulum 82 remains hinged to the pelvis at the ischial and/orpubic area and can be re-oriented with or without implantation of awedge 450 to keep the osteotomy open, as illustrated in FIG. 6B. Thewedge 450 can be a bone autograft or a bone allograft or biocompatiblewedge implant made of metal or metal alloy, and can be designed as apatient-specific wedge implant, similar to those disclosed in commonlyassigned U.S. application Ser. No. 12/714,023, filed Feb. 26, 2010,cross-referenced above and incorporated herein by reference. Theacetabulum 82 can be secured to the pelvis using bone screws and/orplates, similar to those disclosed in the above-referenced U.S.application Ser. No. 12/714,023, filed Feb. 26, 2010.

During the corrective procedure for hip dysplasia, the surgeon typicallydetermines the location and orientation of the desired osteotomies andperforms the osteotomies substantial in a free-hand manner. The presentteaching provide patient-specific acetabular resection guides with thatcan assist and guide the surgeon to perform the osteotomies according toa pre-operative plan of osteotomies designed for the particular patient.Referring to FIGS. 5 and 6, an exemplary patient-specific acetabularresection guide 400 can be used according to the present teachings toperform pre-planned osteotomies and correct developmental hip dysplasiaor related conditions.

The acetabular resection guide 400 provides a patient-specific guidethat is prepared during pre-operative planning for the surgicalprocedure based on a three-dimensional image of the hip joint of thepatient. The three-dimensional image of the hip joint of the patient isdeveloped by commercially available software, as discussed above, usingMRI, CT, fluoroscopy, ultrasound, or other medical scans of theparticular patient. Referring to FIGS. 5 and 6, the acetabular resectionguide 400 includes a three-dimensional curved patient-specificengagement surface 402. The patient-specific engagement surface 402 isdome-shaped and has a complementary shape that matches the acetabulumsocket of the pelvis 80 of the patient for nesting therein in only oneposition. An annular flange 404 extends from a periphery or rim 403 ofthe patient-specific engagement surface 402. The flange 404 has asubstantially flat or planar upper surface 405 and an opposite lowersurface 407 that can be patient-specific at least in some or all of theareas 409 that engage the periacetabular surface of the pelvis 80. Theflange 404 of the acetabular resection guide 400 is designed during thepre-operative plan to define a plurality of elongated through-slots orother resection guiding formations collectively referenced as resectionslots or guiding formations 406.

In one illustrative embodiment, resection slots 406 a, 406 b, 406 c, 406d, 406 e arranged peripherally around the periphery 403 for guiding asaw blade 430 or other cutting instrument to resect the periacetabulararea to separate the acetabulum 82 from the pelvis 80 and enablerelative rotation of the acetabulum 82 relative to the pelvis forcorrection the hip dysplasia using a periacetabular resection procedure.As can be seen in FIG. 5, some of the elongated slots (406 a, 406 b, 406c) may overlap or intersect one another such that after resection, theacetabulum can be rotated relative to the femoral head such that theorientation of the acetabulum is corrected. The orientation and locationof the elongated slots 406 is patient-specific and is determinedpre-operatively to match the acetabulum of the patient for enabling theacetabular resections.

The acetabular resection guide 400 can also include a straight elongatedpatient-specific resection slot 406′ for performing a single resection86 for the procedure described in reference to FIG. 6B. For the singleosteotomy procedure, the acetabulum remains hinged in the ischial andpubic region at a patient-specific location determined by the uncutregion that remains in the acetabulum based on the location of theosteotomy 86 and the corresponding resection slot 406′. The osteotomy 86can be opened to the extent required for improving the alignment betweenthe femoral head 90 and the acetabulum 82 and an implant 450 can beinserted to keep the osteotomy 86 open, as described above.

The acetabular resection guide 400 can also include an arcuate or curvedslot 406″ that can be used optionally in other corrective procedures.The acetabular resection guide 400 can be provided with all or some ofthe above described slots 406, all of which can be designedpre-operatively to be patient-specific and provide the surgeon with morethan one option of performing the procedure based on intra-operativeconsiderations. The various options can be provided in a singleacetabular resection guide 400, as illustrated in FIG. 5. Alternatively,more than one acetabular resection guide 400 can be provided for variouscombinations of slots 406. For example, one acetabular resection guide400 can include only the slots 406 a through 406 e, while anotheracetabular resection guide 400 can include one or both the slots shownin phantom lines 406′ and 406″.

In some instances acetabular dysplasia can be corrected solely byperforming one or more osteotomies and re-orienting the acetabulum, asdescribed above, or in combination with a total or partial hipreplacement, or solely by a hip replacement. Referring to FIGS. 7-9, anacetabular implant 550 can be selected for implantation during thepre-operative stage, with or without re-orientation of the acetabulumdepending on the patient's condition and the surgeon's preferences. Theacetabular implant 550 can be patient-specific and designed during thepre-operative stage based on the three dimensional image of the hipjoint of the patient such that an outer surface 560 of the acetabularimplant 550 matches in a complementary manner with the patient'sacetabulum and other patient-specific kinematic considerations.Alternatively, the acetabular implant 550 can be a commerciallyavailable implant, such as the Regenerex© Ringloc© Modular AcetabularSystem available from Biomet Manufacturing Corp, Warsaw, Ind. Theacetabular implant 550 can include an outer acetabular cup or shell 552and a liner cup 554 that includes an inner cavity 558 for articulatingwith a natural femoral head or a femoral head implant. The outer surface560 of the acetabular shell 552 can be coated or otherwise covered withmaterial promoting ingrowth, such a porous metal, including, forexample, the Regenerex© porous titanium construct commercially availablefrom Biomet Manufacturing Corp, Warsaw, Ind. The acetabular shell 552can include a plurality of apertures 556 for use with fasteners toattach the acetabular shell 552 to the acetabulum 82 of the patient. Theliner cup 554 can be made from a wear-resistant material, including, forexample, polyethylene.

Other anatomic defects can also be associated with the patient'sacetabulum and identified in the medical scans of the hip joint of thepatient. Referring to FIG. 8, for example, a weakened or defective area83 can extend from a periphery 85 of the acetabulum 82 of the patient. Apatient-specific acetabular or periacetabular augment 500 (henceforthcollectively acetabular augment 500) can be prepared during thepreoperative plan to strengthen, fill or replace and generally correctthe defective area 83 and be coupled with the acetabular shell 552, asillustrated in FIGS. 8-9. The acetabular augment 500 can include athree-dimensional curved outer patient-specific surface 502 to match andreplace the defective area 83, with or without any prior milling,burring procedure, as selected by the surgeon during the pre-operativeplanning stage. The outer surface 502 of the acetabular augment 500 canbe covered with ingrowth-promoting material, such as porous titanium,and include a plurality of through apertures 506 for fixation to thepelvis 80. In one embodiment, the apertures can be communicating ordefine a common elongated opening 508. The acetabular augment 500 caninclude an implant-coupling surface 504 shaped and sized to mate and bestacked onto the outer surface 560 of the acetabular shell 552, which,as discussed above, can be custom-made for specific patient or astandard non-custom acetabular shell 552. Additionally, the acetabularaugment 500 can be secured to the acetabular shell 552 with fasteners.

Referring to FIGS. 10-13, anatomic defects identified in the medicalscan of the hip joint of the patient may also include bone defects 92associated with the femoral head 90 and/or cartilage defects 94 in theacetabulum of femoral head 90, or combinations thereof. Such defects canbe corrected with patient-specific implants that can be designed andselected during the preoperative plan based on the three-dimensionalimage of the hip joint of the patient constructed from MRI or CT prother medical scans of the patient, as discussed above.

Referring to FIGS. 10 and 11, a relatively small or superficial bonedefect 92 bounded by a periphery 96 on the bone surface of the femoralhead 90 can be corrected with a patient-specific femoral implant 600.The femoral implant 600 can be shaped as a cap or shell and can includea first or patient-specific three-dimensional curved articulatingsurface 606 that replaces the defective area of the bone defect 92 andis inset or continuous to a remaining healthy surface of the femoralhead 90 for articulation with the acetabulum of the patient or with anacetabular implant. The first surface 606 can be bounded by apatient-specific periphery 608 that matches the periphery 96 of the bonedefect 92. The periphery 96 of the bone defect 92 may be a peripheryafter the bone defect 92 is milled or burred to remove diseased or weakareas or other growths and abnormalities, as applicable for theparticular patient and type of defect present. A recess may also beformed at the periphery 92 for nestingly receiving the femoral implant600. The femoral implant 600 can include a second or bone engagementsurface 602 opposite to the first surface 606. The bone engagementsurface 602 can designed to fit a healthy area underlying the defectafter the bone defect 92 has been removed or cleaned. The femoralimplant 600 can be secured to the bone with pegs, keels, screws or otherfixators 604, which can be either, monolithically attached and integralto the femoral implant or modularly coupled to the femoral implant 600.The femoral implant 600 can be made of any biocompatible material,including metal alloys, such as titanium alloys (Ti-6Al-4V), orcobalt-chromium alloys (Co—Cr—Mo) or ingrowth-promoting porous metal(Regenerex©) or plastic materials including Ultra High Molecular WeightPolyethylene (UHMWPE), PEEK, or other polymers.

Referring to FIGS. 12 and 13, a cartilage defect 94 bounded by aperiphery 98 on the cartilage of the femoral head 90 can be correctedwith a patient-specific femoral implant 650. The femoral implant 650 canbe shaped as a cap or shell and can include a first or patient-specificthree-dimensional curved articulating surface 656 that replaces thedefective area of the cartilage defect 94 and is continuous to aremaining healthy surface of the articular cartilage of the femoral head90. The articulating surface 656 can be bounded by a patient-specificperiphery 658 that matches the periphery 98 of the cartilage defect 94(the periphery 658 is shown as a regular shape in FIG. 13 forsimplicity). The periphery 98 of the cartilage defect 94 may be aperiphery defined after the cartilage defect 94 is trimmed or burred toremove diseased or weak areas or other abnormalities of the cartilage,as applicable for the particular patient and type of defect present, butit generally retains the shape of the defect 94. The femoral implant 650can include a second or bone engagement surface 652 opposite to thearticulating surface 656. The bone engagement surface 652 can bepatient-specific and designed to fit a healthy area underlying thecartilage defect 94 after the cartilage defect 94 has been removed orcleaned. The femoral implant 650 can be secured to the bone with a stem,a peg, a keel or other fixation element 654, which can be either,monolithically attached and integral to the femoral implant or modularlycoupled to the femoral implant 650. The femoral implant 650 can also bepress-fitted or interference fitted or fitted with a cementing agentwith or without biologic or other pharmacologic/antibiotic oringrowth-promoting agents and implanted without the use of a fasteningmember 654. In other embodiments, the fixation element 654 can beresorbable. The femoral implant 650 can be made of pyrolytic carbon,ingrowth-promoting porous metal (Regenerex©), PEEK, or biocompatiblemetal alloys including titanium alloys (Ti-6Al-4V) and cobalt-chromiumalloys (Co—Cr—Mo).

It should be appreciated that defects extending through the articularcartilage into the underlying subchondral bone, i.e., defects includingcartilage and underlying bone, can be similarly corrected with femoralimplant 600 or femoral implant 650.

The present teachings provide various patient-specific instruments,including alignment guides and resection guides for hip jointarthroplasty. The guides can be used with patient-specific implants orwith standard, non custom implants. The present teachings also providepatient-specific implants for the acetabulum and femoral head forcorrecting bone and/or cartilage defects.

The foregoing discussion discloses and describes merely exemplaryarrangements of the present teachings. Furthermore, the mixing andmatching of features, elements and/or functions between variousembodiments is expressly contemplated herein, so that one of ordinaryskill in the art would appreciate from this disclosure that features,elements and/or functions of one embodiment may be incorporated intoanother embodiment as appropriate, unless described otherwise above.Moreover, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. One skilled in the art will readily recognizefrom such discussion, and from the accompanying drawings and claims,that various changes, modifications and variations can be made thereinwithout departing from the spirit and scope of the present teachings asdefined in the following claims.

What is claimed is:
 1. A hip-joint device comprising: a patient-specificacetabular resection guide including: a dome-shaped surface bounded by aperiphery, the dome-shaped surface is a patient-specificthree-dimensional surface designed to anatomically match, and is adaptedto be received into, an acetabulum of a pelvis of the patient in oneposition, based on a three-dimensional image of a hip joint of thepatient reconstructed from a medical scan of the hip joint; and aplurality of guiding formations defined on the resection guide, theguiding formations having patient-specific shapes and orientations forguiding corresponding osteotomies relative to the acetabulum forresecting and separating the acetabulum from the pelvis, and enablingrotation of the acetabulum relative to the pelvis of the patient forcorrecting hip dysplasia of the patient.
 2. The hip-joint device ofclaim 1, wherein the acetabular resection guide includes an annularflange extending from the periphery of the dome-shaped surface, theannular flange having a bone-engaging surface positionable on aperiacetabular area of the acetabulum of the patient, and wherein theplurality of resection guiding formations are defined through theannular flange.
 3. The hip-joint device of claim 2, wherein thebone-engaging surface of the annular flange is patient-specific.
 4. Thehip-joint device of claim 2, wherein the guiding formations areelongated slots for guiding a cutting blade.
 5. The hip-joint device ofclaim 4, wherein at least two of the elongated slots intersect.
 6. Thehip-joint device of claim 2, wherein the elongated slots are arrangedperipherally around the periphery of the dome-shaped surface.
 7. Thehip-joint device of claim 2, wherein at least one guiding formation isan elongated slot designed for an optional single open osteotomy.
 8. Thehip-joint device of claim 2, wherein at least one guiding formation isan elongated arcuate slot.
 9. The hip-joint device of claim 1, furthercomprising: an implantable acetabular shell receivable in the patient'sacetabulum; and an implantable patient-specific acetabular augmentprepared based on a three-dimensional image of the hip joint of thepatient showing an acetabular defect, the acetabular augment having afirst patient-specific surface for correcting the acetabular defect andan opposite second surface mateable with an outer surface of theacetabular shell.
 10. The hip-joint device of claim 9, wherein theacetabular shell is patient-specific.
 11. A hip-joint device comprising:a patient-specific acetabular resection guide including: a dome-shapedsurface bounded by a periphery, wherein the dome-shaped surface is athree-dimensional patient-specific surface designed to anatomicallymatch, and is adapted to be received into an acetabulum of a pelvis of apatient, based on a three-dimensional image of a hip joint of thepatient reconstructed from a medical scan of the hip joint; an annularflange extending from the periphery of the dome-shaped surface, theannular flange having a patient-specific bone-engaging surfaceengageable to a periacetabular area of the acetabulum of the patient,and a plurality of elongated slots defined by the flange and orientedaround the periphery in a patient-specific orientation for guiding acutting instrument to resect and separate the acetabulum from the pelvisin order to rotate the acetabulum relative to the pelvis.
 12. The hipjoint device of claim 11, further comprising: an implantable acetabularshell receivable in the patient's acetabulum; and an implantablepatient-specific acetabular augment prepared based on athree-dimensional image of the hip joint of the patient showing anacetabular defect, the acetabular augment having a firstpatient-specific surface for correcting the acetabular defect and anopposite second surface mateable with an outer surface of the acetabularshell.
 13. A hip-joint device comprising: a patient-specific acetabularresection guide configured to guide resection of bone around theacetabulum and prepare the acetabulum to receive an implantableacetabular shell, the guide including: a dome-shaped surface bounded bya periphery, the dome-shaped surface is a patient-specificthree-dimensional surface adapted to both anatomically match and bereceived into the acetabulum in one position based on athree-dimensional image of a hip joint of the patient reconstructed froma medical scan of the hip joint; an annular flange extending from aperiphery of the dome-shaped surface, the annular flange includes abone-engaging surface positionable on a periacetabular area of thehip-joint around the acetabulum; and a plurality of guiding formationsdefined through the annular flange, the guiding formations includingpatient-specific shapes and orientations for guiding correspondingosteotomies relative to the acetabulum for resecting and separating theacetabulum from the pelvis, and enabling rotation of the acetabulumrelative to a pelvis of the patient to correct hip dysplasia of thepatient.
 14. The hip-joint device of claim 13, further comprising: animplantable patient-specific acetabular augment prepared based on athree-dimensional image of the hip joint of the patient showing anacetabular defect, the acetabular augment having a firstpatient-specific surface for correcting the acetabular defect and anopposite second surface mateable with an outer surface of the acetabularshell.
 15. The hip-joint device of claim 13, wherein the guidingformations are elongated slots for guiding a cutting blade.
 16. Thehip-joint device of claim 13, wherein at least two of the elongatedslots intersect.
 17. The hip-joint device of claim 13, wherein at leastone of the plurality of guiding formations is configured to guide acutting blade to the hip-joint for a single open osteotomy.
 18. Thehip-joint device of claim 13, wherein at least one of the plurality ofguiding formations is an elongated arcuate slot.
 19. The hip-jointdevice of claim 13, wherein at least one of the plurality of guidingformations is angled and adapted to direct saw blades away from theacetabulum.
 20. The hip-joint device of claim 13, wherein the guidingformations are configured to direct saw blades to the hip-joint superiorto the acetabulum and inferior to the acetabulum.